Mkhwebane's report described Zille's actions as a celebration of the oppression, exploitation, racism and poverty.

She recommended that the speaker of the provincial government must within 30 working days take appropriate action to hold Zille accountable.

In statement released immediately after Mkhwebane's report, Zille's office said she is likely to take the report on judicial review.

"The premier has already advised the public protector that, in her view, such a finding would be unlawful and irrational," said the statement.

Adding to this was the ANC Western Cape, which welcomed Mkhwebane's report and said it was vindicated by it.

"ANC in the Western Cape welcomes the Public Protectors report on Zille's colonial tweets.

"As the head of government in the province, Zille's primary responsibility is to build social cohesion and racial harmony in a province that has known too much blood and pain on racial polarization, and this judgment makes this crucial point quite clear.

"As the ANC, we are vindicated by the public protector's remedial action, which now forces the Provincial Legislature, according to its constitutional responsibility, to find appropriate measures to discipline Zille."

Zille apologised for her offensive tweet about colonialism shortly after it sparked outrage and landed her in trouble with the main opposition Democratic Alliance (DA), which she used to lead.